Obsidian Bases Skill

Workflow

Create the file: Create a .base file in the vault with valid YAML content
Define scope: Add filters to select which notes appear (by tag, folder, property, or date)
Add formulas (optional): Define computed properties in the formulas section
Configure views: Add one or more views (table, cards, list, or map) with order specifying which properties to display
Validate: Verify the file is valid YAML with no syntax errors. Check that all referenced properties and formulas exist. Common issues: unquoted strings containing special YAML characters, mismatched quotes in formula expressions, referencing formula.X without defining X in formulas
Test in Obsidian: Open the .base file in Obsidian to confirm the view renders correctly. If it shows a YAML error, check quoting rules below

Schema

Base files use the .base extension and contain valid YAML.

# Global filters apply to ALL views in the base
filters:
  # Can be a single filter string
  # OR a recursive filter object with and/or/not
  and: []
  or: []
  not: []
 
# Define formula properties that can be used across all views
formulas:
  formula_name: 'expression'

Filter Syntax

Filters narrow down results. They can be applied globally or per-view.

Filter Structure

# Single filter
filters: 'status == "done"'
 
# AND - all conditions must be true
filters:
  and:
    - 'status == "done"'
    - 'priority > 3'
 
# OR - any condition can be true
filters:
  or:
    - 'file.hasTag("book")'
    - 'file.hasTag("article")'
 
# NOT - exclude matching items
filters

Filter Operators

Operator	Description
`==`	equals
`!=`	not equal
`>`	greater than
`<`	less than
`>=`	greater than or equal
`<=`	less than or equal
`&&`

Properties

Three Types of Properties

Note properties - From frontmatter: note.author or just author
File properties - File metadata: file.name, file.mtime, etc.
Formula properties - Computed values: formula.my_formula

File Properties Reference

Property	Type	Description
`file.name`	String	File name
`file.basename`	String	File name without extension
`file.path`	String	Full path to file
`file.folder`	String	Parent folder path
`file.ext`	String

The `this` Keyword

In main content area: refers to the base file itself
When embedded: refers to the embedding file
In sidebar: refers to the active file in main content

Formula Syntax

Formulas compute values from properties. Defined in the formulas section.

formulas:
  # Simple arithmetic
  total: "price * quantity"
 
  # Conditional logic
  status_icon: 'if(done, "✅", "⏳")'
 
  # String formatting
  formatted_price: 'if(price, price.toFixed(2) + " dollars")'
 
  # Date formatting
  created: 'file.ctime.format("YYYY-MM-DD")'
 
  # Calculate days since created (use .days for Duration)
  days_old: '(now() - file.ctime).days'
 
  # Calculate days until due date

Key Functions

Most commonly used functions. For the complete reference of all types (Date, String, Number, List, File, Link, Object, RegExp), see FUNCTIONS_REFERENCE.md.

Function	Signature	Description
`date()`	`date(string): date`	Parse string to date (`YYYY-MM-DD HH:mm:ss`)
`now()`	`now(): date`	Current date and time
`today()`	`today(): date`	Current date (time = 00:00:00)
`if()`

Duration Type

When subtracting two dates, the result is a Duration type (not a number).

Duration Fields: duration.days, duration.hours, duration.minutes, duration.seconds, duration.milliseconds

IMPORTANT: Duration does NOT support .round(), .floor(), .ceil() directly. Access a numeric field first (like .days), then apply number functions.

# CORRECT: Calculate days between dates
"(date(due_date) - today()).days"                    # Returns number of days
"(now() - file.ctime).days"                          # Days since created
"(date(due_date) - today()).days.round(0)"           # Rounded days
 
# WRONG - will cause error:
# "((date(due) - today()) / 86400000).round(0)"      # Duration doesn't support division then round

Date Arithmetic

# Duration units: y/year/years, M/month/months, d/day/days,
#                 w/week/weeks, h/hour/hours, m/minute/minutes, s/second/seconds
"now() + \"1 day\""       # Tomorrow
"today() + \"7d\""        # A week from today
"now() - file.ctime"      # Returns Duration
"(now() - file.ctime).days"  # Get days as number

View Types

Table View

views:
  - type: table
    name: "My Table"
    order:
      - file.name
      - status
      - due_date
    summaries:
      price: Sum
      count: Average

Cards View

views:
  - type: cards
    name: "Gallery"
    order:
      - file.name
      - cover_image
      - description

List View

views:
  - type: list
    name: "Simple List"
    order:
      - file.name
      - status

Map View

Requires latitude/longitude properties and the Maps community plugin.

views:
  - type: map
    name: "Locations"
    # Map-specific settings for lat/lng properties

Default Summary Formulas

Name	Input Type	Description
`Average`	Number	Mathematical mean
`Min`	Number	Smallest number
`Max`	Number	Largest number
`Sum`	Number	Sum of all numbers
`Range`	Number	Max - Min

Complete Examples

Task Tracker Base

filters:
  and:
    - file.hasTag("task")
    - 'file.ext == "md"'
 
formulas:
  days_until_due: 'if(due, (date(due) - today()).days, "")'
  is_overdue: 'if(due, date(due) < today() && status != "done", false)'
  priority_label: 'if(priority == 1, "🔴 High", if(priority == 2, "🟡 Medium", "🟢 Low"))'
 
properties:

Reading List Base

filters:
  or:
    - file.hasTag("book")
    - file.hasTag("article")
 
formulas:
  reading_time: 'if(pages, (pages * 2).toString() + " min", "")'
  status_icon: 'if(status == "reading", "📖", if(status == "done", "✅", "📚"))'
  year_read: 'if(finished_date, date(finished_date).year, "")'
 
properties:
  author

Daily Notes Index

filters:
  and:
    - file.inFolder("Daily Notes")
    - '/^\d{4}-\d{2}-\d{2}$/.matches(file.basename)'
 
formulas:
  word_estimate: '(file.size / 5).round(0)'
  day_of_week: 'date(file.basename).format("dddd")'
 
properties:
  formula.day_of_week:
    displayName: "Day"
  formula.word_estimate:
    displayName

Embedding Bases

Embed in Markdown files:

![[MyBase.base]]
 
<!-- Specific view -->
![[MyBase.base#View Name]]

YAML Quoting Rules

Use single quotes for formulas containing double quotes: 'if(done, "Yes", "No")'
Use double quotes for simple strings: "My View Name"
Escape nested quotes properly in complex expressions

Troubleshooting

YAML Syntax Errors

Unquoted special characters: Strings containing :, {, }, [, ], ,, &, *, #, ?, |, -, <, >, =, !, %, @, ` must be quoted.

# WRONG - colon in unquoted string
displayName: Status: Active
 
# CORRECT
displayName: "Status: Active"

Mismatched quotes in formulas: When a formula contains double quotes, wrap the entire formula in single quotes.

# WRONG - double quotes inside double quotes
formulas:
  label: "if(done, "Yes", "No")"
 
# CORRECT - single quotes wrapping double quotes
formulas:
  label: 'if(done, "Yes", "No")'

Common Formula Errors

Duration math without field access: Subtracting dates returns a Duration, not a number. Always access .days, .hours, etc.

# WRONG - Duration is not a number
"(now() - file.ctime).round(0)"
 
# CORRECT - access .days first, then round
"(now() - file.ctime).days.round(0)"

Missing null checks: Properties may not exist on all notes. Use if() to guard.

# WRONG - crashes if due_date is empty
"(date(due_date) - today()).days"
 
# CORRECT - guard with if()
'if(due_date, (date(due_date) - today()).days, "")'

Referencing undefined formulas: Ensure every formula.X in order or properties has a matching entry in formulas.

# This will fail silently if 'total' is not defined in formulas
order:
  - formula.total
 
# Fix: define it
formulas:
  total: "price * quantity"

obsidian-bases

CLI Install

Skill Instructions

Run with Cloud Agent

Obsidian Bases Skill

Workflow

Schema

Filter Syntax

Filter Structure

Filter Operators

Properties

Three Types of Properties

File Properties Reference

The `this` Keyword

Formula Syntax

Key Functions

Duration Type

Date Arithmetic

View Types

Table View

Cards View

List View

Map View

Default Summary Formulas

Complete Examples

Task Tracker Base

Reading List Base

Daily Notes Index

Embedding Bases

YAML Quoting Rules

Troubleshooting

YAML Syntax Errors

Common Formula Errors

References

obsidian-bases

CLI Install

Skill Instructions

Run with Cloud Agent

Obsidian Bases Skill

Workflow

Schema

Filter Syntax

Filter Structure

Filter Operators

Properties

Three Types of Properties

File Properties Reference

The this Keyword

Formula Syntax

Key Functions

Duration Type

Date Arithmetic

View Types

Table View

Cards View

List View

Map View

Default Summary Formulas

Complete Examples

Task Tracker Base

Reading List Base

Daily Notes Index

Embedding Bases

YAML Quoting Rules

Troubleshooting

YAML Syntax Errors

Common Formula Errors

References

The `this` Keyword